Hardening off seedlings – Get your plants transplant-ready!

Hardening off seedlings – Get your plants transplant-ready!

If you are familiar with gardening, you might have heard that “Hardening off seedlings is essential for healthy growth of your seedlings into robust plants”. A good hardening procedure ensures the foundation for your transplant’s health. Here is the complete guide to starting off the hardening off plants.

Hardening off seedlings - Get your plants transplant-ready!

What is hardening?

Plants are very similar to human babies. Before we send our children to school, we will introduce little activities to them and take them outside for play dates, so that they could set up well in the school. The same applies to your plants as well.

Seeds establish into seedlings in a controlled environment in pro-trays with controlled light, nutrients, and water. The external or outdoor conditions are adverse or harsh when compared to the controlled environmental conditions, where seeds germinate and establish into seedlings.

Hardening off is the procedure where the seeds are slowly acclimated or prepared well before they are transplanted in the main field and hardening off also prevents transplantation shock.

Is it necessary to harden off seedlings before transplanting?

The answer is pretty much yes!!! If you transplant your seedlings without hardening, their leaves might scorch up, the plant might die due to transplantation shock (inability of young seedlings to hold direct sun, strong winds and excess or little soil moisture).

How to harden off your seedlings?

How to harden off your seedlings?

Hardening off is generally performed when the seedlings are 2 to 4 weeks age or when they developed at least one set of true leaves. The seed start hardening, and it may take seven to ten days. Here is the step-by-step guide to hardening off your seedlings.

Start hardening in dappled sunlight.

Start hardening in dappled sunlight

It is very important to remember not to be very harsh at the beginning with seeds. The first step of hardening is to bring your seedlings out of the controlled or indoor environment. Find a spot in your yard where it receives dappled or partial sunlight and keep your seedlings for 3 to 4 hours.

Make sure the seedlings are well moisturized before you set them up for hardening and there are more chances of wilt. After keeping them outdoors in a shady spot, place them back in their previous spot. You can repeat this procedure one more day based on your transplantation schedule.

Shift them to bright sunlight in garden.

Shift them to bright sunlight

It’s time for a little promotion for your plant. After exposure to dappled or partial sun, move them to a spot where bright sunlight is available. Expose your plants to the bright afternoon sun for 3 to 4 hours. Take them back indoors at night.

Repeat this process one more day and this time, reduce the amount of water for irrigation. This step prepares the plant for future drought conditions.

Expose your seedling to full light

Expose your seedling to full light

This is the crucial step in hardening off. Make sure you watered your seedlings well. Choose a spot that receives an ample amount of sunlight and place your plant there. Expose it to full sunlight for at least 4 hours and bring them indoors at night. Keep an eye on pests and diseases and you will find any go for neem oil spray. 

A little more sun than yesterday for better hardening

A little more sun than yesterday for better hardening

Your seedling had acclimated well to direct sun. All you need to do now is increase the duration of sunlight. Expose your seedlings to full sun for at least 6 hours and bring them indoors only at night. Repeat this process for one more day and reduce the amount of irrigated water this time.

Keep it outdoors at night to acclimatize for external weather

Keep it outdoors at night to acclimatize for external weather

Exposure your seedlings to direct sun for 6 hours like the former step. Do not bring them indoors at night and leave them throughout the night at the same spot. You can procrastinate this step, if the outdoor night temperatures are too low and the weather is too windy.

 Your seedling is all ready for transplantation in garden.

 Your seedling is all ready for transplantation

Now, it’s time for your little seedling for transplantation. Make sure you are transplanting your seedling at the right depth, and you are following the right spacing. Check them for pests and diseases regularly and support them with a stake if necessary. 

Hardening off plants

Hardening off plants

If you are growing your plants indoors or growing them in a greenhouse or net house, before transplanting your plants to the main field or shifting them outdoors, you need to harden off plants. You can follow the similar procedure discussed above to harden off your plants. In addition to the above steps, hold irrigation or reduce your irrigation frequency to prepare your plants to withstand droughts or periods of low water availability.


  • If you find any seedlings affected by the pest or diseases, it is always advised to isolate them from healthy seedlings and treat them with organic solutions separately for effective pest management.
  • weeds act as carriers for pests and diseases. make your transplantation field weed free by taking up weed management practices like hand weeding and herbicide application.
  • gently brush off your seedlings with your fingers to prepare them to withstand the winds.

Remember these points while hardening off your plants and seedlings.

  • Always use gentle motions for transferring your seedlings and plants from one place to another place.
  • Don’t be too harsh on your plant babies from day 1 of hardening off.
  • Do not go for hardening if the external climatic conditions are too harsh.
  • Do not disturb the root zone of your plant too much while transplanting.
  • Gently uproot your seedlings from pro-trays or grow bags while transplanting to the main field.

Leave a Comment